package com.wolfpire.system.common;

public class MD5 {                                                                         
	  /* 下面这些S11-S44实际上是一个4*4的矩阵，在原始的C实现中是用#define 实现的，             
	  这里把它们实现成为static final是表示了只读，切能在同一个进程空间内的多个                 
	  Instance间共享*/                                                                         
	    static final int S11 = 7;                                                              
	    static final int S12 = 12;                                                             
	    static final int S13 = 17;                                                             
	    static final int S14 = 22;                                                             
	                                                                                           
	    static final int S21 = 5;                                                              
	    static final int S22 = 9;                                                              
	    static final int S23 = 14;                                                             
	    static final int S24 = 20;                                                             
	                                                                                           
	    static final int S31 = 4;                                                              
	    static final int S32 = 11;                                                             
	    static final int S33 = 16;                                                             
	    static final int S34 = 23;                                                             
	                                                                                           
	    static final int S41 = 6;                                                              
	    static final int S42 = 10;                                                             
	    static final int S43 = 15;                                                             
	    static final int S44 = 21;                                                             
	                                                                                           
	    static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0,                          
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,                                  
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,                                  
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };                             
	    /* 下面的三个成员是MD5计算过程中用到的3个核心数据，在原始的C实现中                     
	      被定义到MD5_CTX结构中                                                                
	                                                                                           
	      */                                                                                   
	    private long[] state = new long[4]; // state (ABCD)                                    
	    private long[] count = new long[2]; // number of bits, modulo 2^64 (lsb first)         
	    private byte[] buffer = new byte[64]; // input buffer                                  
	                                                                                           
	  /* digestHexStr是MD5的唯一一个公共成员，是最新一次计算结果的                             
	  　 16进制ASCII表示.                                                                      
	  */                                                                                       
	    public String digestHexStr;                                                            
	                                                                                           
	    /* digest,是最新一次计算结果的2进制内部表示，表示128bit的MD5值.                        
	  */                                                                                       
	    private byte[] digest = new byte[16];                                                  
	                                                                                           
	  /*                                                                                       
	    getMD5ofStr是类MD5最主要的公共方法，入口参数是你想要进行MD5变换的字符串                
	    返回的是变换完的结果，这个结果是从公共成员digestHexStr取得的．                         
	  */                                                                                       
	    public String getMD5ofStr(String inbuf) {                                              
	          md5Init();                                                                       
	          md5Update(inbuf.getBytes(), inbuf.length());                                     
	          md5Final();                                                                      
	          digestHexStr = "";                                                               
	          for (int i = 0; i < 16; i++) {                                                   
	                digestHexStr += byteHEX(digest[i]);                                        
	          }                                                                                
	          return digestHexStr.toLowerCase();                                                             
	                                                                                           
	    }                                                                                      
	    // 这是MD5这个类的标准构造函数，JavaBean要求有一个public的并且没有参数的构造函数       
	    public MD5() {                                                                         
	          md5Init();                                                                       
	                                                                                           
	          return;                                                                          
	    }                                                                                      
	    /* md5Init是一个初始化函数，初始化核心变量，装入标准的幻数 */                          
	    private void md5Init() {                                                               
	          count[0] = 0L;                                                                   
	          count[1] = 0L;                                                                   
	          ///* Load magic initialization constants.                                        
	                                                                                           
	          state[0] = 0x67452301L;                                                          
	          state[1] = 0xefcdab89L;                                                          
	          state[2] = 0x98badcfeL;                                                          
	          state[3] = 0x10325476L;                                                          
	                                                                                           
	          return;                                                                          
	    }                                                                                      
	    /* F, G, H ,I 是4个基本的MD5函数，在原始的MD5的C实现中，由于它们是                     
	    简单的位运算，可能出于效率的考虑把它们实现成了宏，在java中，我们把它们                 
	  　　实现成了private方法，名字保持了原来C中的。 */                                        
	                                                                                           
	    private long F(long x, long y, long z) {                                               
	          return (x & y) | ((~x) & z);                                                     
	                                                                                           
	    }                                                                                      
	    private long G(long x, long y, long z) {                                               
	          return (x & z) | (y & (~z));                                                     
	                                                                                           
	    }                                                                                      
	    private long H(long x, long y, long z) {                                               
	          return x ^ y ^ z;                                                                
	    }                                                                                      
	                                                                                           
	    private long I(long x, long y, long z) {                                               
	          return y ^ (x | (~z));                                                           
	    }                                                                                      
	                                                                                           
	    /*                                                                                     
	      FF,GG,HH和II将调用F,G,H,I进行近一步变换                                              
	      FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.                        
	      Rotation is separate from addition to prevent recomputation.                         
	    */                                                                                     
	                                                                                           
	    private long FF(long a, long b, long c, long d, long x, long s,                        
	          long ac) {                                                                       
	          a += F (b, c, d) + x + ac;                                                       
	          a = ((int) a << s) | ((int) a >>> (32 - s));                                     
	          a += b;                                                                          
	          return a;                                                                        
	    }                                                                                      
	                                                                                           
	    private long GG(long a, long b, long c, long d, long x, long s,                        
	          long ac) {                                                                       
	          a += G (b, c, d) + x + ac;                                                       
	          a = ((int) a << s) | ((int) a >>> (32 - s));                                     
	          a += b;                                                                          
	          return a;                                                                        
	    }                                                                                      
	    private long HH(long a, long b, long c, long d, long x, long s,                        
	          long ac) {                                                                       
	          a += H (b, c, d) + x + ac;                                                       
	          a = ((int) a << s) | ((int) a >>> (32 - s));                                     
	          a += b;                                                                          
	          return a;                                                                        
	    }                                                                                      
	    private long II(long a, long b, long c, long d, long x, long s,                        
	          long ac) {                                                                       
	          a += I (b, c, d) + x + ac;                                                       
	          a = ((int) a << s) | ((int) a >>> (32 - s));                                     
	          a += b;                                                                          
	          return a;                                                                        
	    }                                                                                      
	    /*                                                                                     
	      md5Update是MD5的主计算过程，inbuf是要变换的字节串，inputlen是长度，这个              
	      函数由getMD5ofStr调用，调用之前需要调用md5init，因此把它设计成private的              
	    */                                                                                     
	    private void md5Update(byte[] inbuf, int inputLen) {                                   
	                                                                                           
	          int i, index, partLen;                                                           
	          byte[] block = new byte[64];                                                     
	          index = (int)(count[0] >>> 3) & 0x3F;                                            
	          // /* Update number of bits */                                                   
	          if ((count[0] += (inputLen << 3)) < (inputLen << 3))                             
	                count[1]++;                                                                
	          count[1] += (inputLen >>> 29);                                                   
	                                                                                           
	          partLen = 64 - index;                                                            
	                                                                                           
	          // Transform as many times as possible.                                          
	          if (inputLen >= partLen) {                                                       
	                md5Memcpy(buffer, inbuf, index, 0, partLen);                               
	                md5Transform(buffer);                                                      
	                                                                                           
	                for (i = partLen; i + 63 < inputLen; i += 64) {                            
	                                                                                           
	                    md5Memcpy(block, inbuf, 0, i, 64);                                     
	                    md5Transform (block);                                                  
	                }                                                                          
	                index = 0;                                                                 
	                                                                                           
	          } else                                                                           
	                                                                                           
	                i = 0;                                                                     
	                                                                                           
	          ///* Buffer remaining input */                                                   
	          md5Memcpy(buffer, inbuf, index, i, inputLen - i);                                
	                                                                                           
	    }                                                                                      
	                                                                                           
	    /*                                                                                     
	      md5Final整理和填写输出结果                                                           
	    */                                                                                     
	    private void md5Final () {                                                             
	          byte[] bits = new byte[8];                                                       
	          int index, padLen;                                                               
	                                                                                           
	          ///* Save number of bits */                                                      
	          Encode (bits, count, 8);                                                         
	                                                                                           
	          ///* Pad out to 56 mod 64.                                                       
	          index = (int)(count[0] >>> 3) & 0x3f;                                            
	          padLen = (index < 56) ? (56 - index) : (120 - index);                            
	          md5Update (PADDING, padLen);                                                     
	                                                                                           
	          ///* Append length (before padding) */                                           
	          md5Update(bits, 8);                                                              
	                                                                                           
	          ///* Store state in digest */                                                    
	          Encode (digest, state, 16);                                                      
	                                                                                           
	    }                                                                                      
	                                                                                           
	    /* md5Memcpy是一个内部使用的byte数组的块拷贝函数，从input的inpos开始把len长度的        
	　　　　　 字节拷贝到output的outpos位置开始                                                
	    */                                                                                     
	                                                                                           
	    private void md5Memcpy (byte[] output, byte[] input,                                   
	          int outpos, int inpos, int len)                                                  
	    {                                                                                      
	          int i;                                                                           
	                                                                                           
	          for (i = 0; i < len; i++)                                                        
	                output[outpos + i] = input[inpos + i];                                     
	    }                                                                                      
	                                                                                           
	    /*                                                                                     
	      md5Transform是MD5核心变换程序，有md5Update调用，block是分块的原始字节                
	    */                                                                                     
	    private void md5Transform (byte block[]) {                                             
	          long a = state[0], b = state[1], c = state[2], d = state[3];                     
	          long[] x = new long[16];                                                         
	                                                                                           
	          Decode (x, block, 64);                                                           
	                                                                                           
	          /* Round 1 */                                                                    
	          a = FF (a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */                             
	          d = FF (d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */                             
	          c = FF (c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */                             
	          b = FF (b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */                             
	          a = FF (a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */                             
	          d = FF (d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */                             
	          c = FF (c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */                             
	          b = FF (b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */                             
	          a = FF (a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */                             
	          d = FF (d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */                            
	          c = FF (c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */                           
	          b = FF (b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */                           
	          a = FF (a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */                           
	          d = FF (d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */                           
	          c = FF (c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */                           
	          b = FF (b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */                           
	                                                                                           
	          /* Round 2 */                                                                    
	          a = GG (a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */                            
	          d = GG (d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */                            
	          c = GG (c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */                           
	          b = GG (b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */                            
	          a = GG (a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */                            
	          d = GG (d, a, b, c, x[10], S22, 0x2441453L); /* 22 */                            
	          c = GG (c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */                           
	          b = GG (b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */                            
	          a = GG (a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */                            
	          d = GG (d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */                           
	          c = GG (c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */                            
	          b = GG (b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */                            
	          a = GG (a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */                           
	          d = GG (d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */                            
	          c = GG (c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */                            
	          b = GG (b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */                           
	                                                                                           
	          /* Round 3 */                                                                    
	          a = HH (a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */                            
	          d = HH (d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */                            
	          c = HH (c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */                           
	          b = HH (b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */                           
	          a = HH (a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */                            
	          d = HH (d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */                            
	          c = HH (c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */                            
	          b = HH (b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */                           
	          a = HH (a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */                           
	          d = HH (d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */                            
	          c = HH (c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */                            
	          b = HH (b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */                             
	          a = HH (a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */                            
	          d = HH (d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */                           
	          c = HH (c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */                           
	          b = HH (b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */                            
	                                                                                           
	          /* Round 4 */                                                                    
	          a = II (a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */                            
	          d = II (d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */                            
	          c = II (c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */                           
	          b = II (b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */                            
	          a = II (a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */                           
	          d = II (d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */                            
	          c = II (c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */                           
	          b = II (b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */                            
	          a = II (a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */                            
	          d = II (d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */                           
	          c = II (c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */                            
	          b = II (b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */                           
	          a = II (a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */                            
	          d = II (d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */                           
	          c = II (c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */                            
	          b = II (b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */                            
	                                                                                           
	          state[0] += a;                                                                   
	          state[1] += b;                                                                   
	          state[2] += c;                                                                   
	          state[3] += d;                                                                   
	                                                                                           
	    }                                                                                      
	                                                                                           
	    /*Encode把long数组按顺序拆成byte数组，因为java的long类型是64bit的，                    
	      只拆低32bit，以适应原始C实现的用途                                                   
	    */                                                                                     
	    private void Encode (byte[] output, long[] input, int len) {                           
	          int i, j;                                                                        
	                                                                                           
	          for (i = 0, j = 0; j < len; i++, j += 4) {                                       
	                output[j] = (byte)(input[i] & 0xffL);                                      
	                output[j + 1] = (byte)((input[i] >>> 8) & 0xffL);                          
	                output[j + 2] = (byte)((input[i] >>> 16) & 0xffL);                         
	                output[j + 3] = (byte)((input[i] >>> 24) & 0xffL);                         
	          }                                                                                
	    }                                                                                      
	                                                                                           
	    /*Decode把byte数组按顺序合成成long数组，因为java的long类型是64bit的，                  
	      只合成低32bit，高32bit清零，以适应原始C实现的用途                                    
	    */                                                                                     
	    private void Decode (long[] output, byte[] input, int len) {                           
	          int i, j;                                                                        
	                                                                                           
	                                                                                           
	          for (i = 0, j = 0; j < len; i++, j += 4)                                         
	                output[i] = b2iu(input[j]) |                                               
	                    (b2iu(input[j + 1]) << 8) |                                            
	                    (b2iu(input[j + 2]) << 16) |                                           
	                    (b2iu(input[j + 3]) << 24);                                            
	                                                                                           
	          return;                                                                          
	    }                                                                                      
	                                                                                           
	    /*                                                                                     
	      b2iu是我写的一个把byte按照不考虑正负号的原则的＂升位＂程序，因为java没有unsigned运算 
	    */                                                                                     
	    public static long b2iu(byte b) {                                                      
	          return b < 0 ? b & 0x7F + 128 : b;                                               
	    }                                                                                      
	                                                                                           
	  /*byteHEX()，用来把一个byte类型的数转换成十六进制的ASCII表示，                           
	  　因为java中的byte的toString无法实现这一点，我们又没有C语言中的                          
	    sprintf(outbuf,"%02X",ib)                                                              
	  */                                                                                       
	    public static String byteHEX(byte ib) {                                                
	          char[] Digit = { '0','1','2','3','4','5','6','7','8','9',                        
	          'A','B','C','D','E','F' };                                                       
	          char [] ob = new char[2];                                                        
	          ob[0] = Digit[(ib >>> 4) & 0X0F];                                                
	          ob[1] = Digit[ib & 0X0F];                                                        
	          String s = new String(ob);                                                       
	          return s;                                                                        
	    }                                                                                      
	    public static void main(String args[]){                                                
	        MD5 md5 = new MD5();                                                               
	        System.out.println(md5.getMD5ofStr("123456"));     
	        //CA934D75F6F79DF7C376CBFED86926DB
	        //F17C61771FEAD7C92EA8ED03B1735AD6
	    }

}
